This sanding pad has an elastic structure. It is for fine sanding and sanding of contoured surfaces and has a hardness grade of SW. All Festool pads are designed with dust extraction as a primary consideration, so you'll work cleaner, produce a better finish and significantly extend the life of your abrasives and pads. Festool pads feature the StickFix hook and loop design for quick and efficient abrasive changes, and enable re use of partially used abrasives. A highly resilient, heat resistant MPE foam is utilized in all our pads for consistent finishing results, uniform wearing, and extended pad life. Sanding pads will eventually fatigue and require replacement, therefore it is advisable to keep a fresh pad at hand to avoid a break in work.